Conventionally, it has been practiced that nano-order or micro-order fibers are made by electrospinning, and the electrospun fibers are stacked on a surface of a base sheet. For example, the fibers are made by electrostatically exploding fiber raw material liquids positively-charged.
For stacking the fibers on the surface of the base sheet, it is necessary to electrically neutralize positively-charged fibers having previously stacked on the base sheet by using a collector device. Consequently, an electrostatic repulsion between the positively-charged fibers having previously stacked on the base sheet and the subsequent positively-charged fibers is avoided.
For example, the non-woven fabric manufacturing apparatus described in Patent Document 1 comprises a collector device having a plate-like collecting electrode plane-contacting with a back surface of the base sheet and a voltage supplying device for supplying a negatively-voltage to the collecting electrode. For example, the non-woven fabric manufacturing apparatus described in Patent Document 2 comprises a belt-like collecting electrode plane-contacting with the back surface of the base sheet. According to such collector devices, fibers having previously stacked on the surface of the base sheet are electrically neutralized.
Additionally, the collecting electrode of the collector device functions to electrostatically attract positively-charged fibers to the base sheet. Specifically, the collecting electrode supplied with a negative voltage plane-contacts with the back surface of the base sheet and thereby cause a dielectric polarization by which positive charges are collected at the back surface side and negative charges are collected at the front surface side of the base sheet. Due to the dielectric polarization of the base sheet, the positively-charged fibers are electrostatically attracted to the front surface of the base sheet. Consequently, the fibers are attracted to the front surface of the base sheet.